A stretcher mounted in the ambulance car or the like must be configured to be easily mounted in and fixed to the ambulance car or the like. In emergency rescue situations, there have been proposed many improvements such as adjusting of the height of the stretcher according to emergency patients, the shape of a lifter mounted in the stretcher for transporting the emergency patient, and so on. Herein, the ambulance car or the like (hereinafter referred to as “patient-transporting vehicle”) refers to a vehicle equipped with equipment for transporting the patient and the like in entering or leaving a hospital, going to a hospital, transferring to another hospital, taking to or from social welfare facilities and so on (hereinafter referred to as “stretcher”). Patent document 1 discloses a stretcher including a bed part for placing a sick or injured person, legs that are foldably provided at the bed part and are developed along with the rising of the bed part or folded with the lowering of the bed part, and wheels provided at the legs, and further including an initial lifting device for applying a lifting force to the bed part in an initial stage of a lifting operation of lifting the bed part from a position in a lowest stage to a predetermined intermediate position between the lowest stage and a highest stage.
Patent document 2 discloses a stretcher including constant force springs as slide mechanisms for vertically changing the position of an upper frame of the stretcher, mecha-lock mechanisms for stopping the upper frame of the stretcher at any position, lock mechanisms for fixing sliding of front leg auxiliary frames for assisting front legs of the stretcher, rollers for facilitating sliding between supporting parts of the front legs, the front leg auxiliary frames and rear leg auxiliary frames for assisting rear legs, and a lifter mounted in the stretcher.
Patent document 3 discloses a stretcher mounted in a vehicle comprising a truck part and a lifter part that can be engaged with the truck part, wherein the truck part includes front legs and rear legs that have base parts pivotally attached to lower front and rear parts of a base frame and front ends that can rotate forward and backward, a rolling wheel is attached to each of the front legs and the rear legs, and between the base parts of the front and rear legs and the base frame, a posture switching device for switching the posture between the state where the front legs and the rear legs each rotate forward and backward and fall from a standing state and the state where the standing state is held, and a detection device for detecting the floor surface of the vehicle and causing the posture switching device of the front legs to switch to the state where the front legs can fall backward are provided. The detection device has a back stop mechanism for bringing auxiliary wheels provided at auxiliary frames that can rotate in front of the base parts of the front legs into contact with the floor surface and maintaining the state and a motion mechanism for releasing the lock state of the posture switching device after the auxiliary wheels contacts with the floor surface and the back stop mechanism starts operation.
Although, as described above, the stretcher mounted in the ambulance car or the like has been variously improved, these improvements are not still enough. When an emergency patient is received at a low position in the stretcher with the legs being folded, brake pedals of the rotatable casters of the rear legs are located inner of the stretcher, thereby disadvantageously obstructing application of brakes. A stretcher in Patent document 4 is provided to solve this problem, and is configured to automatically apply brakes when the stretcher is set to the lowest stage. In the case of the stretcher in Patent document 4, the stretcher, when being used on a slope land or the like, can be handled in safety so as not to suddenly move even if the user forgets to brake.
Generally, in the stretcher, fixed casters are attached to the front legs and rotatable casters are attached to rear legs so that longitudinal movement can be rapidly performed in transporting the patient. In the case of using such a stretcher at an intermediate height for, for example, transferring the patient from a bed to the stretcher or transferring the patient from the stretcher to the bed, there is a problem such that the movement to lay the stretcher alongside the bed cannot be smoothly performed since the front casters are fixed. In order to perform cardiac massage in the state where a frame of the stretcher is located at a position lower than the intermediate position or to transport the stretcher at the intermediate height or lower height, it has been expected to realize the stretcher that can be smoothly moved forward and backward and left and right at the intermediate height or lower height.
Patent document 1: Japanese Unexamined Patent Application Publication No. 2005-21626
Patent document 2: WO2004/078087
Patent document 3: Japanese Unexamined Patent Application Publication No. 2003-10250
Patent document 4: Japanese Unexamined Patent Application Publication No. 2008-99952